Why carry out this study?

While anti-citrullinated protein antibodies and rheumatoid factor biomarkers have demonstrated value in diagnosing rheumatoid arthritis (RA) and prognosticating more severe disease, evidence has indicated that these biomarkers may also interact with therapeutic outcomes in RA.

This study analyzed patient-level data from four early RA trials of abatacept and compared clinical outcomes between patients with SeroPositive Early and Active RA (SPEAR) and patients without these characteristics (non-SPEAR) to understand the differential treatment impact of abatacept on various efficacy endpoints.

We hypothesized that abatacept is associated with stronger improvements across multiple efficacy endpoints among SPEAR patients compared to non-SPEAR patients.

What was learned from the study?

This pooled analysis of four abatacept trials demonstrated a differential treatment effect of abatacept on change from baseline to week 24 across various efficacy outcomes among patients with SPEAR versus non-SPEAR, which was not seen with comparators.

The results of this study confirm prior literature demonstrating the predictive value of anti-citrullinated protein antibodies and rheumatoid factor seropositivity in abatacept treatment and highlight the potential utility of serostatus to guide treatment selection.